JPS616157A - Treatment of slag and dust - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is a method of mixing slag and dust generated during refining of molten steel so that it can be used as landfill material, ballast, aggregate, etc. Regarding how to ask questions.

Slag and dust generated during the refining of molten steel are disposed of in landfills as waste, and are also used as road ballast,
Concrete aggregate and other materials can also be used effectively.

However, some steelmaking slags weather and disintegrate into powder over time if left as is. This weathering occurs when free CaO is contained at a certain R or more depending on the relationship with other compositional dispersions.

When it weathers, it expands in volume when it is underground, and when it is underground, it turns into dust and is blown away, becoming a public source. On the other hand, steelmaking dust is generated during the melting and refining process and collected by a dust collector, and is a fine powder mainly composed of Fe, O, and metal oxides such as MnO and ZnO1Sin. Since it is a fine powder, it is scattered in the air by the wind and can only be disposed of as it is, and depending on the type of steel to be melted and refined, it may contain trace amounts of Cr, Pb, Cd, and other heavy metals. Since self-harmful metal ions, such as hexavalent Cr, are eluted due to the above, some kind of immediate action must be taken to render them harmless.

(Prior Art and Problems) Various means for solving the above problem have been considered and implemented in the past. As a measure to prevent the flag from collapsing, various types of anti-collapse materials that combine with free [CaO] are used, partly because the principle of weathering and collapse is known.

The most popular method is to add and mix SiO, Ae, O, etc.

In addition, regarding the dust treatment method, each citrus fruit is treated immediately at high temperature or wet chemically in order to detoxify it, and it is also treated with a pellet to make it easier to handle.

It is being converted into a computer. In addition, since slag and dust are discharged during the steelmaking and refining process, it is convenient to be able to process slag and dust together, and this has also been proposed in a small number of cases.

For example, in JP-A-57-185934, ``Ih molten soot slag electric furnace dust pellets are blown in with Hufflink gas to recover metal oxides containing 11 elements of Zn and Pb which are volatilized, ``Method for turning the contained objects into poison'' was revealed, and also published in Japanese Unexamined Patent Application Publication No. 1989-1989.
888 [Blowing nitrogen, oxygen or air into the molten steelmaking slag to remove electric furnace dust and 10. δ or slag, red θ1−□, force “λmi, masa soil,
Presence in dust by adding and mixing one or more types of slate
The power to turn things into written texts, θ, has been revealed.

However, these things cannot be called 5 things that should be 2 things. In other words, it is possible to carry out Asahikawa 1 for both slag and dust at the same time. , and both of them are made into pellets of Tough!

There are things that aren't. In other words, steelmaking dust is either type 90 or type 4.
5 Miku: “The bonding force between each other is as small as 1 note, or as large as (
On the other hand, if the fluidity is poor, the hopper or piping may cause hanging or clogging, etc., resulting in handling problems.1. Or1. This is because ν is very bad. However, in addition to being expensive, pelletizing the bait as a powder and leaving tag particles behind, which may impair the results of the elution test.

(Means for Solving Problem ζ) The present invention has been made in view of the above, and its gist is to collect powder 4 (4 steel dust) through an immersion nozzle into steelmaking slag in a molten sacrificial state stored in a container. This is a method for treating steelmaking slag and tast, which is characterized by blowing a mixture of dust and sand into a static electric field.

The container g used in the present invention is not special, and may be a general slag pot. The steelmaking slags targeted by the present invention are oxidized TFL slag produced in oxidation refining and G-based V1 slag with high salt content (which causes weathering) produced in reduction smelting.
In it! 11; can also be processed, and its Zokongo Suraku 1
This is also very common. The temperature is in the range 1300-1550°C. Tasto is passed through electric finishing furnaces, ladle refining furnaces, and converter furnaces, and is collected in dust collectors. Rocks crushed into scales such as river sand, sea sand, and mountain sand may also be used. These sands are used to fix the slack mcao.
It contains a large amount of dust and is excellent as an anti-weathering agent, and when mixed with dust, it acts as a carrier for fine dust, making the dust easier to handle.

51 in the furnace. ', salt) it l! i's no 2, 71 in the evening, knock's flow VI is 7. The polymerization ratio of rodanoto and sand, which also works to increase the absorption capacity of umetast, is such that in the case of slag that does not weather, it only acts as a carrier for dust.
The combined Jt is good, but it depends on the Vi shape of the tast and the slag, or even if the ferrous metal is about 01 for the slag 1, it is preferably about 02. The mixing ratio in the case of weathered slag is determined by the rIX of fi447j, which is essential for preventing weathering, and the ratio of the blown tuft.

[Tough] and 6・tσ] are mixed by a powder mixing means of a wakuwari.

The mixture is also blown into the slag using the commonly used method according to Sonos.

",','km runf is within (r20~60"+'
, i degree iron pipe is good. The air blowing speed is set to a level where the air is sufficiently stirred by knocking or stirring, but not so much that the air blows out. Do you want to decide? J: 3~2
On27min is appropriate. Tough 1 blow 9
Although it varies greatly depending on the temperature and composition of 111 of the sand, etc. to be mixed, and the temperature and composition of the smoked puffer fish, in general, F.
When red smoke of e, O, starts to come out, there is a limit W-C, which is about 60 to 20019 per ton of slag. This amount of jib is sufficient to remove all the dust generated by operating the electric furnace by mj+11. The blowing speed is suitably 50 to 200 kq/min based on the mixture.

(The effect is the effect) By carrying out the h method of the present invention described above, the following effects and effects are exhibited. Namely, the blowing nozzle is inserted into the molten slag in the container, and dust and b↓ etc. are generated together with the air. By blowing the mixture into the slag, the slag absorbs the tast without being sufficiently stirred, and becomes stable by combining with the Sin contained in the inverse layer C110 or iI'1 in the slag. By continuing the blowing, the blowing is stopped when the temperature reaches the limit of dust absorption due to the low temperature and the dust, and the dust is turned into i, 'IJ.

The slag modified as described above shows extremely satisfactory results in heavy metal elution tests and roadbed testing. That is, the dust contains a considerable amount of hexavalent chromium (for example, about 10 omg/e is eluted from aJ smelting dust of stainless steel) and lead, or they are not eluted at all from the slag after treatment. This is due to the fact that it is integrated with dust or chemical silica slag, and in the case of hexavalent chromium, it is heated to a high temperature before that.It also shows perfectly good results in regular tests.

(Example 1) Casting '1), mounting, lt/Ti6. After pouring into a regular I- or V-type slag ladle, 4.2 t of sushi ladle remaining in the ladle was poured into 0.71A of residual molten steel. The temperature is 1370℃. Put a lid on the slag pot, and insert a consumable V,-) nsweig with an inner diameter of 32-I+ through the hole in the lid until the tip reaches the boundary between the slag and the remaining molten steel. was injected with a mixture of The mixture was supplied to the blown air by force feeding the blown air piping from a quantitative cutting hopper. The blowing conditions and blowing amounts are shown in Table 1. On the other hand, dust was also collected through a duct installed in the lid. The dust used was melted and refined dust of general low alloy steel. An example of the analysis is shown in Table 3. The sand mixed with the dust had a sea level of 1.1%. An example of the component analysis is shown in Table 4.

The average particle size of Roku was 0.4 mg. The dust and sand were mixed by the falling convergence method. In the case of the second paddle in this example, the temperature was as low as 1370°C since the slag remained in the ladle after degassing and casting in the ladle. The temperature drop during treatment was slower than when there was no residual molten steel, and the amount of dust blown into the slag could be maintained at a satisfactory level of 0.10. (Table 1 All Towns) What are the analysis values of slag after treatment I11? It is shown in the g2 table. In the case of a ladle, residual molten steel always remains, and b'Y'-c is preferably placed together in a slag ladle to suppress the temperature drop of the slag, as in this embodiment.

Satisfactory results were obtained in both cases.

That is, even though the dust contained hexavalent Cr and Pll, no elution occurred in the elution test. As shown in the bearing capacity test, very good results were obtained in the roadbed material test. The solidified floc of the remaining molten steel was used as raw material for the electric furnace.

(Example 2) The oxidized refining slag in the electric furnace was placed in a slag pot containing general low-alloy steel melting refining dust and old sand.

The mixture was blown through. Processing conditions and results are the first
The analysis values of slag and dust before and after treatment are also shown in Tables 2 and 3.

In the case of this example, since the oxidizing slag hardly weathers, the mixing ratio with respect to the dust was set to 015, which is necessary and sufficient as a carrier for the dust. In addition, the temperature of the slag was crystalline, the amount of slag was large, and the fluidity was high, so the dust absorption capacity was high, and the amount of dust that could be blown was as high as 0.13 compared to the slag. The cooled and solidified slag was crushed in the same manner as in Example 1, and an elution test and a roadbed test were conducted. In the elution test, there was no elution of harmful metal ions, and as shown in Tables 5 and 6, in the roadbed test, satisfactory results were obtained in both cases.

Table 1 Implementation conditions of Examples Table 2 Slag analysis of Examples i'l (%) □□□□□□
□□- Table 3: Example of Tust distribution (%) Table 4: Example of sea iron analysis (%) Average particle size -0,4-11 Table 5: Result of i1'cBR test (%) Pass 80%
Table 6 ulL An', 14f4 test (iron continuous method) (%
) Gokuraku, 2Φ or less

Claims (1)

[Claims] (1) A method for treating steelmaking slag and dust, which comprises blowing a mixture of powdered steelmaking dust and sand together with air into molten steelmaking slag contained in a container through an immersion lance.